What Are Waves?
Waves are a means of transferring energy from place to place without moving any matter.
- A wave that vibrates at a right angle to the direction of travel (the typical 'bumpy' shape).
- Examples of transverse waves are light waves and waves in the ocean.
- Oscillates (vibrates) in the same direction as the direction of travel.
- Examples of longitudinal waves are sound waves.
- The amplitude (A) is the maximum distance the particles move from their original point.
- The wavelength of a wave is the siz of one complete wave. The symbol for this is lambda
- If the source vibrates quickly, it will produce many waves per second. This is the frequency (f) and it is measured in Hertz (Hz).
- The period of a wave is the amount of time it takes for the source to produce one wave. It is measured in seconds and the symbol it T.
Reflection Of Waves
When waves hit a barrier, they are reflected, however they can be reflected in different ways, depending on the shape and size of the barrier.
- When waves hit a flat barrier, the angle they hit it is the same as the angle of reflection.
- The angle of incidence is equal to the angle of reflection.
- When waves strike a concave barrier, they converge.
- When waves strike a convex barrier, they diverge (spread out).
Refraction Of Waves
If the medium that a wave has to travel through changes, for example from water to glass, the wavelength of the waves change.
The frequency of the waves does not change, but the waves can speed up or slow down when they change medium.
This causes the wave to change direction slightly when it changes medium due to the change in speed, however this only happens when the barrier is at an angle to the direction that the waves are travelling in.
Diffraction Of Waves
If a barrier with a gap in it is placed in the path of waves, the waves continue to travel through the gap but they change shape as they go through.
If the gap is a large one, the waves continue without much alteration in the direction of travel
If the gap in the barrier id smaller, the waves are diffracted more noticably. Maximum diffraction is reached when the gap in the barrier is the same size as the wavelength of the wave.